Chemical composition of tetraploid Gynostemma pentaphyllum gypenosides and their suppression on inflammatory response by NF‐κB/MAPKs/AP‐1 signaling pathways

摘要

The chemical composition and anti‐inflammatory activity of gypenosides isolated from tetraploid (GP) leaves were investigated. The gypenosides accounted for 7.43 mg/g of the tested GP sample, which were composed of four major saponins including isomers of gypenoside 1 and 2 (C H O ), 3 (C H O ), and 4 (C H O ). Pretreatment of gypenosides reduced mRNA expressions of the proinflammatory mediators in LPS‐stimulated RAW264.7 macrophage cells, such as IL‐6, IL‐1β, COX‐2, and TNF‐α in a dose‐dependent manner. The secreted protein levels of IL‐6 and TNF‐α, and NO production were also decreased by gypenosides within the concentration range of 50–200 μg/ml. Moreover, the mechanism studies demonstrated that gypenosides (200 μg/ml) treatment significantly inhibited the nuclear translocation of nuclear factor‐κB and activator protein 1 (c‐Fos and c‐Jun) through down‐regulating the phosphorylation of their upstream IκB kinase and mitogen‐activated protein kinases (MAPKs), especially that of c‐Jun N‐terminal kinase and extracellular regulated protein kinase(JNK and ERK), but not that of the p38 MAPK. These results suggested that the gypenosides might have potential anti‐inflammatory effect and use for improving human health.